Synthesis,Mechanistic Investigation Of Fluorescent Heteroatom-Doped Carbon Dots And Their Application In The Detection

Carbon dots（CDs）with excellent optical absorptivity,water solubility,high chemical inertness,comparatively modest toxicity and low cost are of great interest in various applications such as chemical sensors,bio-imaging,electronics,and photovoltaics.The research were synthesized two kinds of heteroatom doped CDs（S,N-CDs and Zn-CDs）.Complementary theoretical and comprehensive spectroscopic techniques were employed to derive deep insight into the photoluminescence mechanisms of CDs.The detection of Hg²⁺,H₂O₂ and glucose were established by using these two kinds of CDs.The main results are as follows:1.Sulfur and nitrogen co-doped carbon dots（S,N-CDs）with 55%quantum yield were developed by a facile and efficient method.The S,N-CDs showed strong excitation-independent characteristic with spherical shape about 7.23 nm and high solution dispersibility.The S,N-CDs showed highly stable fluorescence performance over a wide pH values from 6 to 12 and in anextremely oxidizing environment.The reason for the mechanism of the enhanced photoluminescence quantum yield（PLQY）of S,N-CDs is that sulfur and nitrogen doped successfully changed the extent of oxidized carbon of CDs.Finally,S,N-CDs were used as probes for the ultra-trace detection of Hg²⁺in the range of2 to 5000 nM.2.Novel,highly luminescent Zn-CDs was prepared（PLQY up to 33%）via hydrothermal method.The Zn-CDs have spherical shape with an average size of 4 nm.The research showed that orbital level understanding of the enhanced fluorescence exhibited by Zn-CDs.According to Fenton reaction-based mechanism Zn-CDs as an efficient fluorescence probe for the detection of hydrogen peroxide and glucose was also demonstrated.was used for the detection.The Zn-CDs exhibited outstanding capability for responding to H₂O₂ with 10⁸0μM and glucose with 5¹00μM over a wide linear range concentration.Hence,the work showed significant adaptable fluorescence-based protocol with enormous potential for applications in biology.